William j



(No Model.) W. J. FERGUSON.

GAS PUMP. l No. 297,773. Patented Apr. 29, 1884.

WITNESSBS l MW ,wm'

` INVENTOR:

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ATTORNEYS.

UNrTED STATES PATENT. Orrrcn.

VILLIAM FERGUSON, OF BALTIYMOBE, MD., ASSIGNOR OF TWO-THIRDS TO J. OLNEY NORRIS AND ISAAC T. NORBS, BOTH OF SAME PLACE.

GAS-PUMP.

SPECIFICATION forming part of Letters Patent No. 297,773, dated April 29, 1884.

n Application filed November 1, 1883. (No model.)

My invention relates to -pumps for gases orv air, and more particularly to that class of 1C pumps which are employed for changing the tension of a gaseous medium in refrigerating machinery.

The improvements consist inthe peculiar construction and arrangement of the piston,

I 5 which has a valve incorporated in it, and in.

the means for tightening 'up the stuffing-box in the lower end of the cylinder, as will be more fully described hereinafter.

The figure is a vertical section of the pump. In the drawing, A represents the cylinder, which stands upright and is supported upon a frame, B. C is the piston, which is made hollow, and has upon its lower end radial arms connecting with a central hub, a, and forming a spider-frame connection for the pis ton-rod D, which is screwed into this hub and iirmly fastened by a pin. per portion of y the piston.A a funnel shaped valve, E, is arranged, which is fitted in the piston iiush with its upper surface, andhas a central aperture that is tightly closed by a cap-plate, b, that is snugly tted'in the top of the valve with a ground joint, and is screwed or otherwise fastened to the same. Both the upper surface of this plate I) and the valve E are, when the valve is closed, iiush with or in the same plane with the upper surface of the piston. The upper end of the piston-rod,whieh protrudes through the hub a, is reduced in size 4o and extends loosely through a hole in the lower part of the funnel-shaped valve, and is secured by a nut, c, in the middle of the valve. J ust here will be seen the use of, cap-plate b, which is to be removed in order to give access to the top of the piston-rod to apply or remove the nut and still preserve a dat flush face for the piston, to permit the latter to close "up tightly against the head of the cylinder and expel all the air, as is necessary in all ef- In the central up-.

' ttedY set-screw behind it.

fective air or gas pumps. The funnel-shaped valve, it will be seen, has a loose up-and-down play on the -reduced end of the piston-rod sufficient to allow said valve to open and close on its seat. G-as or air is taken intoV the cylinder through pipe E2, opening into the bottom ofthe same, and passes up through the piston and its valve, and is expelled through the valve F, whose face is iiush with the inner surface of the upper cylinder-head. Thus on the downstroke of the piston gas passes up through the same and lifts its valve, passing to the upper side of the piston andiilling the chamber on that side. Then on the upward stroke of the piston the gas is compressed and forced out through ,the valve F in the top cylinder- 65 head. G is this cylinder-head,which is bolted to the cylinder and is castrwith a chamber, e, into which the valve F opens, and from which the compressedgases are carried away through outlet f. The cylinder-head G is formed with 7o,

a central opening in its top, having ilanged `edges g, which opening` is closed by a anged cap, H, bolted with a tight joint to the flanges g of the Cylinderhea'd. This cap has a hole in its center to receive and guide the stem of valve F as the latter plays up and down. Above this stem is placed a spiral spring, t', whose tension may be regulated by a tightly- At'the lower end the cylinder has secured a detachable-head, I, y8o bolted between the anges of the cylinder and the supporting-frame B, and the supportingframe has formed with it a downwardly-projecting gland, j, of larger diameter than the piston-rod. In the lower end of this gland, and surrounding the piston-rod, is a4 tube, 7c, between which and the cylinder-head there is left a space for stuffing, which may be compressed by the upward movement of the tube k to form a tight stuffing-box for the piston- 9o rod. To force this tube up, I screw-thread the lower exterior portion of the gland j and screw onto it a nut, Z, whose lower portion is formed into a ratchet-wheel, m. Around the exterior of this nut there swivels a ring, to which is lattached a lever, at, which has a spring-pawl,

o, that engages with the ratchetfwheel, so that by oscillating this lever n the ratchet-wheel is turned, the attached nut screwed up, and the tube k is pressed more tightly against the packing on the stuffing-box.

Having thus described lnyinvention, what I claim as neviv is- 1. The combination, with a hollow piston, of a rod secured to one end of the piston and having a headed end wholly Within the piston7 and an upwardlyopening valve having` its upper face flush with the upper end of the piston when said valve is closed7 and arranged upon the end of the rod to slide thereon and be guided and limited in its motion7 substantially as described. l

' 2. The combination ofthe hollow piston C, the rod D7 secured to one end of the piston, and having a headed end, the valve E, having j, the tube la, the nut I, provided with ratchet m, and a lever bearing a pawl for said ratchet and swivelednpon a support concentric with relation to said ratchet, substantially as and :for the purpose described.

WILLIAM J. FERGUSON.

vVitnessesz Fnnrx R. SULLUAN, J. OLNHY Noimrs. 

